Acoustic impedance testing device for die cutting piece material
By designing acoustic impedance testing device for die-cutting material, using acoustic wave channels and microphones to measure the acoustic impedance of die-cutting material, the problem that traditional methods cannot be applied to die-cutting material is solved, and the acoustic performance of die-cutting material is achieved. Evaluate.
Patent Information
- Application Number
- CN202420753496.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-12
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-04-12
AI Technical Summary
Traditional acoustic impedance measurement methods are mainly suitable for bulk materials, but not for die-cutting materials, making it difficult to accurately measure the acoustic impedance performance of die-cutting materials.
A die-cut material acoustic impedance testing device is designed, including first and second connecting plates, equipped with a sound source and a microphone, and the sound pressure of the reference sample and the sample to be tested is measured through the acoustic wave channel to calculate its acoustic impedance, and Improve the accuracy and stability of the test using sealing rings and mounting chambers.
Accurate measurement of the acoustic impedance of die-cutting materials is achieved, the accuracy and stability of the test are improved, and it is suitable for evaluating the acoustic performance of die-cutting materials.
Smart Images
Figure CN222259258U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of acoustic performance testing, in particular to a device for testing acoustic impedance of die-cutting material. Background Art
[0002] Die-cut parts have specific shapes, sizes and functions. In the field of acoustics, die-cut parts are used to make dust screens, waterproof membranes, etc., to adjust acoustic damping, improve acoustic performance or protect internal devices from external environmental interference. Traditional acoustic impedance measurement methods are mainly applicable to bulk materials, not die-cut materials. Utility Model Content
[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a die-cut material acoustic impedance testing device, which can be used to measure the acoustic impedance performance of the die-cut material.
[0004] On the one hand, the embodiment of the utility model provides a die-cut material acoustic impedance testing device, comprising:
[0005] A first connecting plate is provided with a first channel penetrating two opposite surfaces of the first connecting plate, a sound source component covering the first channel is installed on the first surface of the first connecting plate, a first installation cavity communicating with the first channel is provided on the side wall of the first connecting plate, and a first microphone is installed in the first installation cavity;
[0006] The second connecting plate is provided with a second channel running through two opposite surfaces of the second connecting plate, the side wall of the second connecting plate is provided with a second installation cavity connected to the second channel, a second microphone is installed in the second installation cavity, the first surface of the second connecting plate is connected to the second surface of the first connecting plate, and the position of the second channel is adapted to the first channel to form a first sound wave channel, at least one of the first surface of the second connecting plate and the second surface of the first connecting plate is provided with a third installation cavity, the third installation cavity is used to install a reference sample covering the first channel and the second channel, the second surface of the second connecting plate and located on the peripheral side of the second channel is provided with a fourth installation cavity, the fourth installation cavity is used to install a sample to be tested.
[0007] The embodiments of the present invention have at least the following beneficial effects:
[0008] In this embodiment, a sound wave is emitted to a first sound wave channel through a sound source component, and a first sound pressure at a front end of a reference sample is measured through a first microphone, and a second sound pressure at a front end of a sample to be tested is measured through a second microphone. The acoustic impedance of the sample to be tested can be measured based on the first sound pressure, the second sound pressure and the acoustic impedance of the reference sample.
[0009] According to some embodiments of the present invention, a first groove is provided on the first surface of the first connecting plate and is located on the peripheral side of the first channel, and a first sealing ring is installed in the first groove.
[0010] According to some embodiments of the present invention, a second groove is provided on the second surface of the second connecting plate and is located on the peripheral side of the second channel, and a second sealing ring is installed in the second groove.
[0011] According to some embodiments of the utility model, the outer wall of the first microphone is connected to the first mounting block, the end of the first mounting block is provided with a third groove, a third sealing ring is installed in the third groove, and the third sealing ring is sleeved on the outer wall of the first microphone and abuts against the inner wall of the first mounting cavity.
[0012] According to some embodiments of the utility model, the outer wall of the second microphone is connected to the second mounting block, the end of the second mounting block is provided with a fourth groove, a fourth sealing ring is installed in the fourth groove, and the fourth sealing ring is sleeved on the outer wall of the second microphone and abuts against the inner wall of the second mounting cavity.
[0013] According to some embodiments of the present invention, a fixing plate covering the reference sample is mounted on the second surface of the first connecting plate, and an avoidance hole for avoiding the first sound wave channel is provided on the fixing plate.
[0014] On the other hand, the present invention provides a device for testing acoustic impedance of die-cutting materials, including:
[0015] A first connecting plate is provided with a first channel penetrating two opposite surfaces of the first connecting plate, a sound source component covering the first channel is installed on the first surface of the first connecting plate, a first installation cavity communicating with the first channel is provided on the side wall of the first connecting plate, and a first microphone is installed in the first installation cavity;
[0016] a third connecting plate, provided with a third channel penetrating two opposite surfaces of the third connecting plate, a side wall of the third connecting plate provided with a fifth installation cavity connected with the third channel, a third microphone installed in the fifth installation cavity, a first surface of the third connecting plate connected with the second surface of the first connecting plate, and a position of the third channel adapted to the first channel to form a second sound wave channel, a sixth installation cavity provided on at least one of the first surface of the third connecting plate and the second surface of the first connecting plate, and the sixth installation cavity used to install a reference sample covering the first channel and the third channel;
[0017] A calibration piece is provided with a cavity in the middle, and the calibration piece is connected to the second surface of the third connecting plate and covers the third channel so that the cavity is connected to the third channel.
[0018] The embodiments of the present invention have at least the following beneficial effects:
[0019] In this embodiment, a sound wave is emitted to the first sound wave channel through a sound source component, and a first sound pressure at the front end of a reference sample is measured through a first microphone. Based on the principle of electroacoustic equivalent analogy and using the known volumetric structure acoustic impedance, the acoustic impedance of the reference sample is measured to facilitate further measurement of the acoustic impedance of the sample to be tested.
[0020] According to some embodiments of the present invention, a first groove is provided on the first surface of the first connecting plate and is located on the peripheral side of the first channel, and a first sealing ring is installed in the first groove.
[0021] According to some embodiments of the present utility model, a fifth groove is provided at the connection between the third connecting plate and the calibration component, and a fifth sealing ring is installed in the fifth groove.
[0022] According to some embodiments of the utility model, the outer wall of the third microphone is connected to the third mounting block, the end of the third mounting block is provided with a sixth groove, a sixth sealing ring is installed in the sixth groove, and the sixth sealing ring is sleeved on the outer wall of the third microphone and abuts against the inner wall of the fifth mounting cavity.
[0023] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:
[0025] Figure 1 This is one of the structural schematic diagrams of the acoustic impedance testing device for die-cutting materials according to an embodiment of the utility model;
[0026] Figure 2 for Figure 1 A schematic cross-sectional view of a device for testing acoustic impedance of die-cutting materials is shown;
[0027] Figure 3 for Figure 1 One of the exploded structural diagrams of the die-cut material acoustic impedance testing device (hidden sound source component);
[0028] Figure 4 for Figure 1 The second structural explosion diagram of the die-cut material acoustic impedance testing device (hidden sound source component);
[0029] Figure 5 for Figure 1 A schematic diagram of the structure of a first microphone of a die-cut material acoustic impedance testing device is shown;
[0030] Figure 6 This is the second structural schematic diagram of the acoustic impedance testing device for die-cutting materials according to an embodiment of the utility model.
[0031] Reference numerals:
[0032] Reference sample 10, first connecting plate 100, first channel 101, first mounting cavity 102, first groove 103, first sealing ring 110, fixing plate 120, avoidance hole 121, second connecting plate 200, second channel 201, second mounting cavity 202, third mounting cavity 203, fourth mounting cavity 204, second groove 205, second sealing ring 210, sound source component 300, first microphone 400, first mounting block 410, third groove 411, third sealing ring 420, second microphone 500, second mounting block 510, fourth sealing ring 520, third connecting plate 600, third channel 601, fifth mounting cavity 602, calibration component 700, cavity 701, fifth groove 702, fifth sealing ring 710, third microphone 800, third mounting block 810, sixth sealing ring 820. DETAILED DESCRIPTION
[0033] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.
[0034] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0035] In the description of the present utility model, "several" means one or more, "multiple" means more than two, greater than, less than, and exceeding are understood as not including the number itself, and "above", "below", and "within" are understood as including the number itself. If there is a description of "first", "second", etc., it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0036] In the description of the present invention, unless otherwise clearly defined, words such as “setting”, “installation”, and “connection” should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention based on the specific content of the technical solution.
[0037] The acoustic impedance test of die-cut materials involves multiple fields such as acoustics, material science and testing technology, and aims to evaluate the performance of die-cut materials during the propagation of sound waves. This testing technology is of great significance in understanding the acoustic properties of materials, optimizing product design, and improving product quality.
[0038] Die-cut materials, especially thin mesh or film materials, exhibit unique acoustic impedance characteristics during the propagation of sound waves, which may be affected by many factors such as the composition, structure, density and elasticity of the material. Therefore, the acoustic impedance test of die-cut materials requires specific test methods and equipment to accurately measure the propagation speed and transmission characteristics of sound waves in the material.
[0039] Traditional acoustic impedance measurement methods are mainly applicable to bulk materials. Therefore, new testing technologies need to be developed for the acoustic impedance testing of die-cut materials. These new technologies may need to combine material properties such as thickness, flexibility, sound absorption performance, etc. to provide accurate test results.
[0040] When testing the acoustic impedance of die-cut materials, it is also necessary to consider the control of the test environment. Factors such as temperature, humidity, and noise may affect the test results. In addition, the accuracy and stability of the test equipment are also key to ensuring the accuracy of the test results.
[0041] Please refer to Figure 1 and Figure 2The present embodiment discloses a device for testing acoustic impedance of die-cutting material, including a first connecting plate 100 and a second connecting plate 200. The first connecting plate 100 is provided with a first channel 101 penetrating two opposite sides of the first connecting plate 100. For example, the first side of the first connecting plate 100 faces downward, the second side of the first connecting plate 100 faces upward, and the first channel 101 penetrates the first side and the second side of the first connecting plate 100. A sound source component 300 covering the first channel 101 is installed on the first side of the first connecting plate 100. For example, the sound source component 300 is a speaker. A first installation cavity 102 communicating with the first channel 101 is provided on the side wall of the first connecting plate 100. A first microphone 400 is installed in the first installation cavity 102. The second connecting plate 200 is provided with a second channel 201 penetrating two opposite sides of the second connecting plate 200. For example, the first side of the second connecting plate 200 faces the first connecting plate 100, the second side of the second connecting plate 200 faces upward, and the second channel 201 penetrates the first side and the second side of the second connecting plate 200. The side wall of the second connecting plate 200 is provided with a second installation cavity 202 connected to the second channel 201, and the second microphone 500 is installed in the second installation cavity 202. The first surface of the second connecting plate 200 is connected to the second surface of the first connecting plate 100, and the position of the second channel 201 is adapted to the first channel 101 to form a first sound wave channel. Please refer to Figure 3 and Figure 4 , at least one of the first surface of the second connecting plate 200 and the second surface of the first connecting plate 100 is provided with a third installation cavity 203, illustratively, the third installation cavity 203 is provided on the first surface of the second connecting plate 200, or, the third installation cavity 203 is provided on the second surface of the first connecting plate 100, or, the first surface of the second connecting plate 200 is provided with a first sub-cavity, the second surface of the first connecting plate 100 is provided with a second sub-cavity, and the first sub-cavity and the second sub-cavity constitute the third installation cavity 203. The third installation cavity 203 is used to install the reference sample 10 covering the first channel 101 and the second channel 201, and the second surface of the second connecting plate 200 and located on the peripheral side of the second channel 201 is provided with a fourth installation cavity 204, and the fourth installation cavity 204 is used to install the sample to be tested.
[0042] In this embodiment, the sound source component 300 emits sound waves to the first sound wave channel, and measures the first sound pressure at the front end of the reference sample 10 through the first microphone 400, and measures the second sound pressure at the front end of the sample to be tested through the second microphone 500. The acoustic impedance of the sample to be tested can be measured based on the first sound pressure, the second sound pressure and the acoustic impedance of the reference sample 10.
[0043] Please refer to Figure 3 and Figure 4A first groove 103 is provided on the first surface of the first connecting plate 100 and on the peripheral side of the first channel 101. A first sealing ring 110 is installed in the first groove 103. The first sealing ring 110 can seal the connection between the first connecting plate 100 and the sound source component 300 to avoid leakage of sound waves, which is beneficial to improving the accuracy of the test.
[0044] A second groove 205 is provided on the second surface of the second connecting plate 200 and located on the peripheral side of the second channel 201. A second sealing ring 210 is installed in the second groove 205. The second sealing ring 210 can seal the connection between the sample to be tested and the second connecting plate 200, reduce the interference of the external environment on the test, and help improve the accuracy of the test.
[0045] Please refer to Figure 4 and Figure 5 The outer wall of the first microphone 400 is connected to the first mounting block 410, and the end of the first mounting block 410 is provided with a third groove 411, and a third sealing ring 420 is installed in the third groove 411. The third sealing ring 420 is sleeved on the outer wall of the first microphone 400 and abuts against the inner wall of the first mounting cavity 102. The first microphone 400 is inserted into the first mounting block 410, and the first mounting block 410 is installed in the first mounting cavity 102 by fasteners such as screws and pins. The third sealing ring 420 can improve the installation sealing of the first microphone 400, avoid sound wave leakage, and help improve the accuracy of the test.
[0046] Please continue to refer to Figure 4 and Figure 5 , similar to the installation method of the first microphone 400, the outer wall of the second microphone 500 is connected to the second mounting block 510, and the end of the second mounting block 510 is provided with a fourth groove, and the structure of the fourth groove is the same as that of the third groove 411, which will not be described in detail here, and a fourth sealing ring 520 is installed in the fourth groove, and the fourth sealing ring 520 is sleeved on the outer wall of the second microphone 500 and abuts against the inner wall of the second mounting cavity 202. The second microphone 500 is inserted into the second mounting block 510, and the second mounting block 510 is installed in the second mounting cavity 202 by fasteners. The fourth sealing ring 520 can improve the installation sealing of the second microphone 500, avoid sound wave leakage, and help improve the accuracy of the test.
[0047] Please refer to Figure 3 The second surface of the first connecting plate 100 is provided with a fixing plate 120 covering the reference sample 10, and a avoiding hole 121 for avoiding the first acoustic wave channel is provided on the fixing plate 120. During installation, the reference sample 10 is placed in the first installation cavity 102, and the reference sample 10 is locked and fixed by the fixing plate 120, thereby improving the installation reliability of the reference sample 10.
[0048] Please refer to Figure 6 In order to obtain the acoustic impedance of the reference sample 10, it is necessary to calibrate the reference sample 10 before testing the sample to be tested. To this end, the present embodiment also provides a die-cutting material acoustic impedance testing device, including a first connecting plate 100, a third connecting plate 600 and a calibration piece 700, please refer to Figure 2 and Figure 6 The first connecting plate 100 is provided with a first channel 101 penetrating two opposite surfaces of the first connecting plate 100, a sound source element 300 covering the first channel 101 is installed on the first surface of the first connecting plate 100, a first installation cavity 102 communicating with the first channel 101 is provided on the side wall of the first connecting plate 100, a first microphone 400 is installed in the first installation cavity 102, a third connecting plate 600 is provided with a third channel 601 penetrating two opposite surfaces of the third connecting plate 600, a fifth installation cavity 602 communicating with the third channel 601 is provided on the side wall of the third connecting plate 600, a third microphone 800 is installed in the fifth installation cavity 602, and the first surface of the third connecting plate 600 is connected to the first connecting plate 100. The second surface of the calibration piece 700 is connected, and the position of the third channel 601 is adapted to the first channel 101 to form a second sound wave channel. At least one of the first surface of the third connecting plate 600 and the second surface of the first connecting plate 100 is provided with a sixth mounting cavity, wherein the arrangement of the sixth mounting cavity is similar to that of the third mounting cavity 203 and will not be described in detail here. The sixth mounting cavity is used to install a reference sample 10 covering the first channel 101 and the third channel 601. A cavity 701 is provided in the middle of the calibration piece 700, wherein the volume of the cavity 701 is fixed and known. The calibration piece 700 is connected to the second surface of the third connecting plate 600 and covers the third channel 601, so that the cavity 701 is connected to the third channel 601.
[0049] In this embodiment, sound waves are emitted to the first sound wave channel through the sound source component 300, and the first sound pressure at the front end of the reference sample 10 is measured through the first microphone 400. Based on the principle of electroacoustic equivalent analogy and using the known volumetric structure acoustic impedance, the acoustic impedance of the reference sample 10 is measured to facilitate further measurement of the acoustic impedance of the sample to be tested.
[0050] Please refer to Figure 4 A first groove 103 is provided on the first surface of the first connecting plate 100 and on the peripheral side of the first channel 101. A first sealing ring 110 is installed in the first groove 103. The first sealing ring 110 can seal the connection between the first connecting plate 100 and the sound source component 300 to avoid leakage of sound waves, which is beneficial to improving the accuracy of the calibration test.
[0051] Please refer to Figure 6A fifth groove 702 is provided at the connection between the third connecting plate 600 and the calibration piece 700. For example, the fifth groove 702 is provided on the surface of the third connecting plate 600. Alternatively, the fifth groove 702 is provided on the surface of the calibration piece 700. A fifth sealing ring 710 is installed in the fifth groove 702. The fifth sealing ring 710 can seal the connection between the third connecting plate 600 and the calibration piece 700 to avoid leakage of sound waves, thereby helping to improve the accuracy of the calibration test.
[0052] Please continue to refer to Figure 6 The outer wall of the third microphone 800 is connected to the third mounting block 810, and a sixth groove is arranged at the end of the third mounting block 810. The structure of the sixth groove is the same as that of the third groove 411, which will not be described in detail here. A sixth sealing ring 820 is installed in the sixth groove. The sixth sealing ring 820 is sleeved on the outer wall of the third microphone 800 and abuts against the inner wall of the fifth mounting cavity 602. The third microphone 800 is penetrated by the third mounting block 810, and the third mounting block 810 is installed in the fifth mounting cavity 602 by fasteners such as screws and pins. The sixth sealing ring 820 can improve the installation sealing of the third microphone 800 and avoid sound wave leakage, which is beneficial to improving the accuracy of the calibration test.
[0053] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.
Claims
1. A device for testing acoustic impedance of die-cutting materials, characterized in that: include: A first connecting plate (100) is provided with a first channel (101) penetrating two opposite surfaces of the first connecting plate (100); a sound source component (300) covering the first channel (101) is installed on the first surface of the first connecting plate (100); a first installation cavity (102) communicating with the first channel (101) is provided on a side wall of the first connecting plate (100); a first microphone (400) is installed in the first installation cavity (102); A second connecting plate (200) is provided with a second channel (201) penetrating two opposite surfaces of the second connecting plate (200); a second installation cavity (202) communicating with the second channel (201) is provided on a side wall of the second connecting plate (200); a second microphone (500) is installed in the second installation cavity (202); a first surface of the second connecting plate (200) is connected to a second surface of the first connecting plate (100), and a position of the second channel (201) is adapted to the first channel (101) to form a first sound wave channel; a third installation cavity (203) is provided on at least one of the first surface of the second connecting plate (200) and the second surface of the first connecting plate (100); the third installation cavity (203) is used to install a reference sample (10) covering the first channel (101) and the second channel (201); a fourth installation cavity (204) is provided on the second surface of the second connecting plate (200) and located on the peripheral side of the second channel (201); the fourth installation cavity (204) is used to install a sample to be tested.
2. The die-cut material acoustic impedance testing device according to claim 1, characterized in that: A first groove (103) is provided on the first surface of the first connecting plate (100) and is located on the peripheral side of the first channel (101), and a first sealing ring (110) is installed in the first groove (103).
3. The die-cut material acoustic impedance testing device according to claim 1 or 2, characterized in that: A second groove (205) is provided on the second surface of the second connecting plate (200) and is located on the peripheral side of the second channel (201), and a second sealing ring (210) is installed in the second groove (205).
4. The die-cut material acoustic impedance testing device according to claim 1, characterized in that: The outer wall of the first microphone (400) is connected to a first mounting block (410), a third groove (411) is provided at the end of the first mounting block (410), a third sealing ring (420) is installed in the third groove (411), and the third sealing ring (420) is sleeved on the outer wall of the first microphone (400) and abuts against the inner wall of the first mounting cavity (102).
5. The die-cut material acoustic impedance testing device according to claim 1 or 4, characterized in that: The outer wall of the second microphone (500) is connected to a second mounting block (510), a fourth groove is provided at the end of the second mounting block (510), a fourth sealing ring (520) is installed in the fourth groove, and the fourth sealing ring (520) is sleeved on the outer wall of the second microphone (500) and abuts against the inner wall of the second mounting cavity (202).
6. The die-cut material acoustic impedance testing device according to claim 1, characterized in that: A fixing plate (120) covering the reference sample (10) is mounted on the second surface of the first connecting plate (100), and an avoidance hole (121) for avoiding the first sound wave channel is provided on the fixing plate (120).
7. A device for testing acoustic impedance of die-cutting materials, characterized in that: include: A first connecting plate (100) is provided with a first channel (101) penetrating two opposite surfaces of the first connecting plate (100); a sound source component (300) covering the first channel (101) is installed on the first surface of the first connecting plate (100); a first installation cavity (102) communicating with the first channel (101) is provided on a side wall of the first connecting plate (100); a first microphone (400) is installed in the first installation cavity (102); A third connecting plate (600) is provided with a third channel (601) penetrating two opposite surfaces of the third connecting plate (600); a side wall of the third connecting plate (600) is provided with a fifth installation cavity (602) connected to the third channel (601); a third microphone (800) is installed in the fifth installation cavity (602); a first surface of the third connecting plate (600) is connected to a second surface of the first connecting plate (100), and a position of the third channel (601) is adapted to the first channel (101) to form a second sound wave channel; a sixth installation cavity is provided on at least one of the first surface of the third connecting plate (600) and the second surface of the first connecting plate (100); the sixth installation cavity is used to install a reference sample (10) covering the first channel (101) and the third channel (601); A calibration piece (700) is provided with a cavity (701) in the middle thereof, and the calibration piece (700) is connected to the second surface of the third connecting plate (600) and covers the third channel (601) so that the cavity (701) is in communication with the third channel (601).
8. The die-cut material acoustic impedance testing device according to claim 7, characterized in that: A first groove (103) is provided on the first surface of the first connecting plate (100) and is located on the peripheral side of the first channel (101), and a first sealing ring (110) is installed in the first groove (103).
9. The die-cut material acoustic impedance testing device according to claim 7 or 8, characterized in that: A fifth groove (702) is provided at the connection between the third connecting plate (600) and the calibration piece (700), and a fifth sealing ring (710) is installed in the fifth groove (702).
10. The die-cut material acoustic impedance testing device according to claim 7, characterized in that: The outer wall of the third microphone (800) is connected to a third mounting block (810), and a sixth groove is provided at the end of the third mounting block (810), and a sixth sealing ring (820) is installed in the sixth groove. The sixth sealing ring (820) is sleeved on the outer wall of the third microphone (800) and abuts against the inner wall of the fifth mounting cavity.